Curiosity studies Mars surroundings, nears drive

This mosaic image shows part of the left side of NASA's Curiosity rover and two blast marks from the descent stage's rocket engines. The rim of Gale Crater is the lighter colored band across the horizon. The back of the rover is to the left. The blast marks can be seen in the middle of the image. Several small bits of rock and soil, which were made airborne by the rocket engines, are visible on the rover's top deck. // Credit: NASA/JPL-Caltech

NASA’s Mars rover Curiosity has been investigating the martian weather around it and the soil beneath it, as its controllers prepare for the car-sized vehicle’s first drive on Mars.

The rover’s weather station, provided by Spain, checks air temperature, ground temperature, air pressure, wind, and other variables every hour at the landing site in Gale Crater. On a typical martian day, or “sol,” based on measurements so far in the two-week-old mission, air temperatures swing from 28° to –103° Fahrenheit (–2° to –75° Celsius). Ground temperatures change even more between afternoon and pre-dawn morning, from 37° to –132° F (3° to –91° C).

“We will learn about changes from day to day and season to season,” said Javier Gómez-Elvira of the Center for Astrobiology in Madrid, Spain, principal investigator for the suite of weather sensors called the Rover Environmental Monitoring Station (REMS).

One of the two sets of REMS wind sensors is not providing data. “One possibility is that pebbles lofted during the landing hit the delicate circuit boards on one of the two REMS booms,” said Ashwin Vasavada from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “We will have to be more clever about using the remaining wind sensor to get wind speed and direction.”

An instrument provided by Russia is checking for water bound into minerals in the top 3 feet (1 meter) of soil beneath the rover. It employs a technology that is used in oil prospecting on Earth, but it had never before been sent to another planet.

“Curiosity has begun shooting neutrons into the ground,” said Igor Mitrofanov of the Space Research Institute in Moscow. “We measure the amount of hydrogen in the soil by observing how the neutrons are scattered, and hydrogen on Mars is an indicator of water.”

The most likely hydrogen to be found in the shallow ground of Gale Crater, near the martian equator, is in hydrated minerals. These are minerals with water molecules, or related ions, bound into the crystalline structure of rocks. They can tenaciously retain water from a wetter past after all free water has gone.

Curiosity will soon have a different patch of ground beneath it. Yesterday, the six-wheeled rover wiggled its four corner wheels side to side for the first time on Mars as a test of the steering actuators on those wheels. This was critical preparation for Curiosity’s first drive on Mars.

“Late tonight, we plan to send Curiosity the commands for doing our first drive tomorrow,” Michael Watkins of JPL said yesterday.

The Mars Science Laboratory spacecraft delivered Curiosity to Mars on August 6 EDT. In a two-year prime mission, researchers are using the rover’s 10 instruments to assess whether the selected study area has ever offered environmental conditions favorable for microbial life and for preserving evidence about whether life has existed.